HTB

Flight is a hard Windows machine that starts with a website with two different virtual hosts. One of them is vulnerable to LFI and allows an attacker to retrieve an NTLM hash. Once cracked, the obtained clear text password will be sprayed across a list of valid usernames to discover a password re-use scenario. Once the attacker has SMB access as the user s.moon he is able to write to a share that gets accessed by other users. Certain files can be used to steal the NTLMv2 hash of the users that access the share. Once the second hash is cracked the attacker will be able to write a reverse shell in a share that hosts the web files and gain a shell on the box as low privileged user. Having credentials for the user c.bum, it will be possible to gain a shell as this user, which will allow the attacker to write an aspx web shell on a web site that’s configured to listen only on localhost. Once the attacker has command execution as the Microsoft Virtual Account he is able to run Rubeus to get a ticket for the machine account that can be used to perform a DCSync attack ultimately obtaining the hashes for the Administrator user.

Editor is an easy Linux box.

CodePartTwo

Sauna is an easy difficulty Windows machine that features Active Directory enumeration and exploitation. Possible usernames can be derived from employee full names listed on the website. With these usernames, an ASREPRoasting attack can be performed, which results in hash for an account that doesn’t require Kerberos pre-authentication. This hash can be subjected to an offline brute force attack, in order to recover the plaintext password for a user that is able to WinRM to the box. Running WinPEAS reveals that another system user has been configured to automatically login and it identifies their password. This second user also has Windows remote management permissions. BloodHound reveals that this user has the DS-Replication-Get-Changes-All extended right, which allows them to dump password hashes from the Domain Controller in a DCSync attack. Executing this attack returns the hash of the primary domain administrator, which can be used with Impacket’s psexec.py in order to gain a shell on the box as NT_AUTHORITY\SYSTEM.

Forest is an easy Windows machine that showcases a Domain Controller (DC) for a domain in which Exchange Server has been installed. The DC allows anonymous LDAP binds, which are used to enumerate domain objects. The password for a service account with Kerberos pre-authentication disabled can be cracked to gain a foothold. The service account is found to be a member of the Account Operators group, which can be used to add users to privileged Exchange groups. The Exchange group membership is leveraged to gain DCSync privileges on the domain and dump the NTLM hashes, compromising the system.

Active is an easy to medium difficulty machine, which features two very prevalent techniques to gain privileges within an Active Directory environment.

Eighteen is an easy Windows machine…

Photobomb is an easy Linux machine where plaintext credentials are used to access an internal web application with a Download functionality that is vulnerable to a blind command injection. Once a foothold as the machine’s main user is established, a poorly configured shell script that references binaries without their full paths is leveraged to obtain escalated privileges, as it can be ran with `sudo

Precious is an Easy Difficulty Linux machine, that focuses on the Ruby language. It hosts a custom Ruby web application, using an outdated library, namely pdfkit, which is vulnerable to CVE-2022-25765, leading to an initial shell on the target machine. After a pivot using plaintext credentials that are found in a Gem repository config file, the box concludes with an insecure deserialization attack on a custom, outdated, Ruby script.

Signed is a medium Windows machine, exposing Microsoft SQL Server and a Domain Controller. It’s part of Season 9.